Methylolphosphoric triamides

ABSTRACT

Methylolphosphoric triamides, for examples, hexamethylolphosphoric triamide, useful for rendering combustible cellulosic fabrics flame resistant.

United States Patent [191 Burke Dec. 17, 1974 METHYLOLPHOSPl-IORICTRIAMIDES [75] Inventor: Patrick Michael Burke, Wilmington,

Del.

[73] Assignee: E. I. du Pont de Nemours and Company, Wilmington, Del.

22 Filed: I June 12,1972

21 Appl.No.: 261,813

FOREIGN PATENTS OR APPLICATIONS OTHER PUBLICATIONS Hellmann, NewerMethod of Preparative Organic Chemistry, Vol. II, p 278-79 (Edited byFoerst) (Academic Press, NY.) (1963).

Primary E.\'aminerHarry l. Moatz [57] ABSTRACT Methylolphosphorictriamides, for examples, hexamethylolphosphoric triamide, useful forrendering combustible cellulosic fabrics flame resistant.

6 Claims, N0 Drawings Great Britain 260/551 METHYLOLPHOSPHORIC TRIAMIDESBACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to methylolphosphoric triamidcs.

2. Description of the Prior Art Phosphorus-containing compounds are wellknown for their ability to impart flame resistance to fabrics. Compoundswhich are known for this purpose includetetra(hydroxymethyl)-phosphonium chlorides, aziridinyl phosphine oxidesand the methylol amide of the dimethyl ester ofbis(carboxyethyl)-phosphonic acid. Many of the prior art compounds maybe undesirable as flame retardants for fabrics because they stiffen thefabric, because of their toxicity, because they must be employed inlarge quantities to impart any significant flame resistance to thefabric, or because they are readily removable by laundering.

German Pat. No. 1,009,629 discloses flame retarding phosphorus compoundswhich are obtained by treating phosphoric triamide with formaldehyde andmethanol. The product, which includes phosphorus esters andhexamethylenetetramine, appears to lack durability to laundering.

British Pat. No. 1,222,885 discloses as flame retardants for cellulosicmaterials, compounds or combinations of compounds which contain nitrogenand phosphorus. It further discloses that fabrics treated with such acompound or combination of compounds have a good degree of flameresistance if the nitrogen content is equal to or greater than 6 minus 4times the phosphorus content and, preferably, is at least 2.5 times thephosphorus content, with the preferred amounts of nitrogen andphosphorus totaling at least 3.5 percent, based on the weight of fabric.Exemplary of compounds containing both nitrogen and phosphorus arephosphoric triamides (phosphoramides) having the formula i wherein R issubstituted or unsubstituted C alkyl, with hydroxyalkyl being apreferred substituted alkyl group.

US. Pat. No. 2,661,342 discloses that combustible cellulosic materialscan be rendered flame resistant with a resinous aminoplast condensationproduct in combination with the reaction product of phosphorusoxychloride and ammonia, the reaction product having a nitrogen tophosphorus atomic ratio of 2.1 to 2.3 and a molecular weight of 180 to300. Aminoplast condensation products are defined therein as resinsderived from amino (including imino) or amido (including imido))compounds, a typical example being a ureaformaldehyde resin (ModernPlastics 17, 433, 1939). Other aminoplast resins are described by C.Ellis in Chemistry of Synthetic Resins," Chapter 26, Reinhold PublishingCo., 1935.

SUMMARY OF THE INVENTION It is an object of this invention to providecompositions which are highly effective in imparting flame resistance tocombustible cellulosic materials. Another object is to providephosphorus-containing compositions which impart flame resistance to suchcellulosic materials. Still another object is to provide flame resis'tant cellulosic materials. A further object is to provide such flameresistant materials which are durable to laundering. Still anotherobject is to provide a method for imparting flame resistance tocombustible cellulosic materials, which method employs aqueous solutionsof phosphorus-containing compounds.

In summary, the present invention resides in the discovery ofmethylolphosphoric triamides which are useful for imparting flameresistance to combustible cellulosic materials, the triamides having theformula wherein at least one of the six R groups is Cl-l Ol-l and theremainder if any are 1-1, said triamide being characterized by thepresence in its P,31 nuclear magnetic resonance (NMR) spectrum of a bandin the range 15-20 ppm. downfield from percent aqueous phosphoric acidas external standard. The invention includes the process of applyingsuch triamides to combustible cellulosic materials and, also, thematerials which are made flame resistant with such triamides.

DETAILED DESCRIPTION OF THE INVENTION This invention is based upon thediscovery that the methylolphosphoric triamides as defined above aremore effective than prior art compounds of similar structure inimparting flame resistance to combustible cellulosic materials, such asfabrics, and that fabrics can be treated with such methylolphosphorictriamides without substantial alteration of their physicalcharacteristics, such as stiffness or hand. As noted above, themethylolphosphoric triamides of this invention contain one to sixmethylol substituents (designated as R in the formula). The remainingnitrogen substituents if any (also designated as R in the formula) arehydrogen. In order to simplify the following discussion, the number ofmethylol groups in the compound of the above formula will be designatedas n methylol groups, with n having the value 1 to 6. correspondingly,the number of hydrogen atoms in the compound of the above formula willbe designated 6-n.

The compounds of this invention are all water soluble. As the number nof methylol groups increases, the compounds become more hygroscopic.Analyses of the compounds of this invention by nuclear magneticresonance show that when the three nitrogen atoms are less thancompletely substituted with methylol groups, that is, n is less than 6,the compounds are actually mixtures of compounds. It is to beunderstood, therefore, that the n values reported for such mixturesrepresent average values, and further, that n need not be a wholenumber. When the nitrogen atoms are completely substituted with methylolgroups (n is 6), the triamide exhibits a single P-3l NMR peak at 16.9ppm. When n is 1 but less than 6, the triamide exhibits a P-31 NMR peakin the range 15-20 ppm. When n is about 3, there is an unsymmetricalpeak at about 18.3 ppm. At higher values of n this peak shifts in itscenter to a lower resonance value; at lower values of n, to a higherresonance value.

The compounds of this invention can be prepared by reacting phosphorictriamide and formaldehyde, for example, as a 37 weight percent aqueoussolution, in an aqueous medium having a pH of 7-1 1, preferably9.5-10.5, obtained by the addition of a base, until the P-31 NMRspectrum of the reaction mixture downfield from 85 percent phosphoricacid as the external standard shows peaks in a band at -20 ppm.Preferably, the signal at 22.5 ppm. indicating unreacted phosphorictriamide disappears; normally, this occurs when n exceeds about 1.5. Thereaction proceeds readily at 5-50C., preferably at -25C., and phosphorictriamide readily binds as many as 6 molar equivalents of formaldehyde.Under the preferred conditions the reaction is completed in 1.5-2 hours.The NMR spectrum after 15 minutes exhibits two signals in a band at15-20 ppm. and after about 90 minutes exhibits a peak in this range, thepeak being centered according to the value of n. The P-3l NMR spectrumprovides a ready means of monitoring the reaction. After completion ofthe reaction, the pH is decreased, for example, by the addition ofhydrochloric acid, to 6.5-7.5, preferably to 6.9-7.3. A curing catalystand/or an aminoplast resin precondensate (both discussed hereinafter)can be added at this stage, either immediately or after the reactionmixture is diluted with water to the desired methylolphosphoric triamideconcentration.

Although it is preferred to use the compounds of this invention directlyas formed in solution in the reaction mixture, they can be isolated byneutralizing the reaction mixture after completion of the reaction, forexample, by adjusting the pH to 7.1-7.5, and the vacuum stripping offthe solvent at a solution temperature not in excess of 50C. The isolatedcompounds are solids or viscous liquids which can be redissolved inaqueous media, from which the compounds can be applied to thecombustible cellulosic material which is to be rendered flame resistant.

The compounds of this invention wherein n is less than 6 have limitedstorage stability in aqueous solution. Such aqueous solutions generallyshould be employed within about 4 hours of preparation in order toimpart durable flame resistance. The instability of such aqueoussolutions is evident from a study of the P-31 NMR spectrum. Upon aging.the aqueous solution becomes acid, the P-31 NMR spectrum becomes morecomplex and there may be noted a decrease in the amount of materialhaving peaks in the 15-20 ppm. range. Correspondingly, the flameresistance imparted to combustible cellulosic materials with such agedaqueous solutions is less fast to laundering.

The efflciency, on a weight basis, of the compounds of this inventionvaries with the value of n. Combustible cellulosic materials are mostefficiently rendered flame resistant by the (monoto tri-lmethylolcompounds, less efficiently by the (tetrato hexa-)methy1ol compounds.Preferred are the (diand tri-)methylol compounds. Only slight loss ofhand accompanies treatment of fabrics with the (monoto tri-)methylolcompounds while a greater loss of hand accompanies the use of the(tetrato hexa-)methylol compounds.

The flame resistance imparted to combustible cellulosic materials by thecompounds of this invention is made durable to laundering by curing thecompounds after they have been applied to the substrates from an aqueoussolution. After application the material is dried by heating at atemperature up to C, preferably at 100-115C. Curing is effected byheating the dried material at -190C., preferably at -170C., in thepresence of an acidic curing catalyst for 2-10 minutes, preferably 2-4minutes. The cat- 1 alyst usually is dissolved in the aqueous solutionof methylolphosphoric triamide before the latter is applied to thematerial being treated. The catalyst usually is added to such aqueoussolution, such as a padbath, in an amount which is 0.5-5 weight percent,preferably 1-2.5 percent, based on the weight of the solution.Optionally, the drying and curing steps can be carried out at the curingtemperature.

1n the cured condition, fabrics treated with methylolphosphorictriamides of this invention lose very little flame resistance after thefirst laundering; fabrics which have been treated with the diand highermethylol phosphoric triamides retain their flame resistance even afterbeing subjected to multiple launderings. During the curing step, thecompounds of this invention are converted to insoluble polymericmaterials, thus rendering them durable to laundering. This explanationof durability is not intended as limiting since it is recognized that anentirely different mechanism or a combination of mechanisms may beinvolved in the flxing operation. For example, it is recognized thatdurability, in part, may be the result of chemical bonding between thecompounds of this invention and the substrate cellulosic material. 1

Preferred curing catalysts are acids which are relatively nonvolatile atcuring temperatures and latent acid compounds. Examples of these includeoxalic, glycolic, lactic, malic, tartaric, succinic and citric acids,ammonium chloride, ammonium sulfates, ammonium phosphates, such asdiammonium acid phosphate, acid salts of organic amines, such as2-methyl-2- aminopropanol-l hydrochloride and tris(2-hydroxyethyl)aminehydrochloride, and salts of weakly basic metals and strong acids, suchas zinc nitrate, zinc chloride, zinc fluoborate, magnesium chloride andmagnesium nitrate.

The compounds of this invention impart flame resistance to'combustiblecellulosic materials by their application to or incorporation into thematerial in amounts of 10-60 weight percent, based on the dry weight ofthe material being treated. Generally, the amount added is 14-50percent, preferably 14-25 percent. The compounds can be applied orincorporated in any suitable fashion. Conveniently, they are applied as5-65 weight percent aqueous solutions by a padding operation;preferably, the aqueous solution contains 15-50 percent of amethylolphosphoric triamide of this invention.

The aqueous solution of methylolphosphoric triamide can contain wettingagents, for example, non-ionic wetting agents, to facilitate wetting ofthe cellulosic material being treated. Included among such wettingagents are polyethylene oxides obtained by reacting a phenol or amonohydric or polyhydric aliphatic alcohol with ethylene oxide. Suchwetting agents generally are added so as to comprise 0.01-0.15 weightpercent of the aqueous triamide solution.

If the aqueous padbath method of application is employed, the padbath,for example, the preparative reactive mixture described above, at a pHof 6.5-7.5, is padded onto the substrate to the extent of 50-120percent, based on the dry weight of substrate, preferably to the extentof 60-90 percent. Padding can be effected by soaking the fabric in thepadbath and squeezing out the excess solution, thus providing control ofthe net amount of solution applied to or picked up by the fabric, Thefractions of the solutions retained by and squeezed out of the fabricare of essentially the same composition. Preferably, the curing catalystis incorporated into the padbath. Drying and curing are carried out aspreviously described. Conveniently, continuously circulating hot air canbe employed as a heat source, especially for the drying operation.

Instead of padding the solution onto the fabric which is to be treated,other convenient means of application can be employed. For example, thesolutions of the compounds of this invention can be sprayed, incontrolled amounts, onto moving fabrics.

The compounds of this invention can be employed in combination withwell-known aminoplast resin condensates which, in some instances,improve the effectiveness of the compounds of this invention inrendering cellulosic materials flame resistant. It also has beendiscovered that the aminoplast resins, in some instances, improve thedurability of the compounds of this invention when both have beencoapplied to the substrate. Aminoplast resins are well known in the artand have been discussed hereinabove. Many such resins are known toimpart flame resistance to cellulosic materials. They often are appliedas water soluble precondensate compounds. When such precondensates areemployed herein, they are dissolved in the freshly prepared solution ofthe methylolphosphoric triamide, which solution then is preferably usedpromptly to treat the fabric, for example, within about 4 hours.

When a methylolphosphoric triamide of this invention is employed incombination with a water soluble aminoplast resin precondensate, lessthan the previously recited amounts of the triamide are necessary toimpart the desired flame resistant characteristics to the cellulosicmaterial being treated. When used in such a combination, themethylolphosphoric triamide is incorporated into or applied to thematerial in amounts 7-15 weight percent, preferably 8-l2 percent, basedon the dry weight of material being treated. The amount of aminoplastprecondensate added in combination with the trimethylolphosphorictriamide is known from the art. When the aminoplast resin precondensateis a hydroxymethylmelamine, a convenient amount is 7-13 weight percent,based on the dry weight of material being treated, preferably 7-10percent.

Water soluble aminoplast resin precondensate compounds useful with thecompounds of this invention include those containing at least two molesof condensed formaldehyde, as N-hydroxymethyl or N-alkoxymethyl groupswherein the alkoxy group contains 1-4 carbon atoms. Precondensatecompounds include polymethylol derivatives, as well as their partial orcomplete ethers, of amides such as urea, thiourea, guanidine anddicyandiamide, for example, dimethylolurea, tetramethylol urea,di(methoxymethyl)urea, dimethylolquanidine, trimethylol quanidine anddimethyloldicyandiamide. Precondensate compounds of substituted ureascan also be used, such as formaldehyde condensates, and their ethers, ofethylene urea. methyleneurea. acetylenediurea, biuret,oxydimethyleneurea (uron) and iminodimethyleneurea (triazone).Particular examples of these include dimethylolethyleneurea,dimethylolmethyleneurea, tetramethylolacetylenediurea,trimethylolbiuret, di(methoxymethyl)uron and di(methoxymethyl) triazone.

Still other precondensate compounds include the reaction products offormaldehyde and triazines such as melamine, diaminotriazine,formoguanamine and 2-chloro-4,6-diaminotriazine. Preferred examples ofsuch precondensates include diand trimethylolmelamine, optionallypartially methylated, hexa(methoxymethyl)melamine,tetramethyloldiaminotriazine andtetramethylol-2-chloro-4,6-diaminotriazine. Diazines and azoles are alsouseful aminoplast resin precondensate compounds. Typical of these areprecondensates based on 2,4-diamino-l,3-diazine, guanazole anddiaminopyrrole.

As previously indicated, fabricswhich are treated with the compounds ofthis invention substantially retain their original physicalcharacteristics, such as soft ness and hand. Even when the compounds ofthis invention are employed in combination witha aminoplast resinprecondensates, because of the small quantity of each compound required,the properties of the fabric are altered only slightly, especially withthe preferred aminoplast resin precondensates and the preferredmethylolphosphoric triamides.

The compounds of this invention and their combinations with aminoplastresin precondensate compounds are particularly effective on combustiblecellulosic materials of a fibrous nature. In the textile field, thisincludes cotton, the preferred fiber, linen, viscose rayon, cuprammoniumrayon, jute, hemp and ramie. Such cellulosic material can be treated inthe form of raw fiber, carded stock, rovings, thread, yarn and felts aswell as inthe form of knitted and woven fabrics. However, the cellulosicmaterial need not be fibrous to be rendered fire resistant with thecompounds of this invention; any cellulosic material can be treated ifit can be penetrated or swollen by water, thus permitting penetration bythe aqueous medium containing the methylolphosphoric triamide. Fibrouscellulosic material can be rendered flame resistant with the compoundsof this invention even though it is blended with other fibers, forexample, natural animal fibers such as wool and synthetic fibers such aslinear polyamide, linear polyester and polyacrylic fibers.

Cellulosic materials which have been rendered flame resistant with thecompounds of this invention are especially useful in tents, stagescenery, upholstery fabrics, slipcovers, draperies, wearing apparel forpersonnel in close contact with fire or heat, bedding, nightclothes,tarpaulins, insulation, padding, rope, string and twine. Fabrics whichhave been treated with the compounds of this invention are flameresistant throughout, not just on their surfaces.

In the following examples, parts are parts by weight except whereotherwise specified. The terms hand, padding, laundering, limitingoxygen index (LOl), vertical flame test (VFT) and char length refer tothe following:

Hand: the softness of a treated fabric relative to untreated fabric asthe control. It is graded subjectively here on a scale of l to 5 inwhich 5 signifies a softness and flexibility virtually indistinguishablefrom the control and l signifies great stiffness relative to the controlPadding: wetting the fabric with the aqueous triamide solution and thenrunning the wet fabric between rollers to squeeze out liquid which is inexcess of the desired pickup on the fabric.

Laundering, also expressed as home washing (HW): exposing the fabric toa standard laundering cycle, employing a washing solution of 100 gramsof a commercial detergent (Tide) per 15 gallons of water, and tumbledrying the washed fabric.

Limiting Oxygen lndex: determined with a -inch by 2-inch piece of fabricspread lengthwise in a vertical plane and supported along its verticaledges. The spread fabric is positioned inside a transparent circular(cylindrical) column open only at the top. The top of the column is oneor more inches above the spread fabric. The interior of the column isprovided with an upward flow, from its base, of a gaseous mixture ofpure oxygen and pure nitrogen. The volume flow rate of each gas makingup the mixture is instrumented and manually adjustable. To test fabricin this apparatus, the spread fabric is ignited from the top while gasmixture flows up the column. The flow rates of the nitrogen and oxygenare adjusted until the flame on the ignited fabric just goes out. Theratio of the volume flow of oxygen to the sum of the volume flows ofoxygen and nitrogen is then calculated. This value, called the LimitingOxygen Index or LOl, is the average of two determinations. As a standardof reference, untreated 8-oz. cotton twill used in the followingexamples to test the effectiveness of the compounds of this inventionhas an LOI value of 0. 1 80fl).002 and is completely burned up in thevertical flame test. Air contains about 21 mole percent oxygen;therefore, fabrics with LOl values below about 0.210 can be expected toburn freely in a candlelike manner (from the top to the bottom) in air.For commercial applications, an LOI value of at least about 0.260-0.270is considered acceptable.

Vertical Flame Test and Char Length: carried out in a 12-inch by 12-inchcabinet 30 inches high and having a glass front. Gas circulation isprovided by a 4-inch high opening beneath the glass front and a 6-inchdiameter baffled hole at the top of the cabinet. It is provided withholder brackets on which a specimen holder is hung. The specimen holderprovides a 2-inch wide by 14-inch high vertical open space and verticalside clips to hold edges of fabric which span this open space. Samplesare ignited by a 6-inch high Bunsen burner having a 0.375-inch insidediameter tube and a luminous flame 1.5 inches long. To conduct the test,a 2.75- inch by -inch fabric sample is held in the specimen holder byits vertical edges and the specimen holder is hung centrally by theholder brackets. The igniting flame is applied so that 0.75 inch of thelower end of the fabric is in the flame. This exposure is continued for3.0 seconds and the flame is removed. After the flame has extinguisheditself, the sample is removed from the holder. A hook with an attachedweight is inserted into the sample on one side of the charred area 0.25inch from the outside edge and 0.25 inch from the lower edge. For 2.0 to6.0-oz. per square yard fabric, the attached weight is 0.25 pound; forover 6.0 and up to and including 15-oz. per square yard fabric, a 0.50pound weight is used. The corner of the cloth at the opposite edge ofthe char from the load is gently raised until the sample and weight areclear of supporting surface. The length of the tear which occurs ismeasured (in inches) and reported as char length. Where char length isreported below, it is understood to have been determined by thisprocedure and to be an average value of 2 or 4 determinations.

EXAMPLE 1 Trimethylolphosphoric Triamide Preparation 9.5 Parts (0.1mole) of phosphoric triamide, prepared according to Klement and Koch,Berichte 87, 338 (1954) and 25 parts of 37 percent aqueous formaldehyde(0.3 mole) were mixed at 20C. and the pH of the resulting solution wasadjusted to 10.3 with 20 percent aqueous sodium hydroxide. The solutionwas allowed to stand for 2.5 hours, after which time the pH of thesolution had dropped to 9.9 and the P-3 1 NMR spectrum showed a bandbetween 15 and 20 ppm. with an unsymmetrical peak centered at 18.3 ppm.;the spectrum was free of a signal at 22.5 ppm. The pH of the solutionwas then adjusted to 7.6 with 10 percent hydrochloric acid. Water wasrapidly stripped from the solution at 20 mm. of Hg pressure and 50C.(using a Rotovac still). 20.2 Parts of residue (theoretical: 18.5 parts)were obtained as an extremely viscous mass which, on standing, became asoft transparent solid. This solid was chemically analyzed. Calcd for CH O N P: C, 19.5; H, 6.5; N, 22,7; P, 16.8; Atomic N/P ratio, 3.0.Found: C, 19.8; H, 6.6; N, 21.1; P, 15.9; Atomic N/P ratio, 2.9.

EXAMPLE 2 Hexamethylolphosphoric Triamide Preparation 0.1 Mole ofphosphoric triamide and 0.72 mole of formaldehyde (37 percent aqueoussolution) were reacted at a pH of 10.2 as described in Example 1. Therewas no drop in pH of the solution after standing. The product insolution showed a single P-3l NMR peak versus percent phosphoric acid at16.9 ppm. Adjustment of the pH to 7.6 with 10 percent hydrochloric acidfollowed by stripping of water at 50C. and 20 mm. of Hg pressureprovided 32.0 parts (theoretical: 27.5 parts) of a colorless viscousliquid residue which was analyzed by chemical analysis. Calcd for C H ON P: C, 26.2; H, 6.6; N, 15.3; P, 11,3. Found: C, 33.5; H, 7.6; N, 13.0;P, 9.6. Since the 37 percent aqueous formaldehyde solution employed inthis experiment had been stabilized with 10-15 percent methanol, it isbelieved that etherification of the methylol groups may have occurredduring stripping. The P-31 NMR spectrum of the product redissolved inwater showed peaks at 16.9 ppm. (for the hexaformaldehyde adduct) and at1 1.3 ppm. (believed to correspond to methoxymethyl derivatives ofphosphoric triamide). The analytical results confirm the presence ofalmost three methoxy groups in the product (replacing almost threehydroxy groups of the hexamethylolphosphoric triamide). Calcd. for C H ON P: C, 34.0; H, 7.6; N, 13.2; P, 9.8.

EXAMPLE 3 Methylolphosphoric Triamide/Trimethylolmelamine Treatment ofCotton Fabric Seven padbaths were prepared so as to contain equalamounts of phosphoric triamide (PTA), 0.5 weight percent ammoniumchloride (curing agent) and trimethylolmelamine (TMM) in an amount 1.67times the PTA. To six of the baths were added 1, 2, 3, 4, 5 and 6 molarequivalents. respectively, of formaldehyde, as a 37 percent aqueoussolution. The formaldehyde and PTA were allowed to react at a pH of 10at 20C. for 2 hours, after which the pH was adjusted to 7.5.

Eight-ounce cotton twill fabrics were impregnated in the padbaths andsqueezed to a net pickup on the fabrics approximating 6.6% PTA and 11.0%TMM. The fabrics were heated at 100C. until dry to the touch and thencured at 170C. for 4 minutes. They were chemically analyzed as cured,tested for L01, laundered once (one home wash) and rate for hand,laundered 19 more times (total, 20 home washes) and then chemicallyanalyzed and tested for L01. The results are summarized in the followingtable.

Mole Ratio CH QI PTA Analysis After Cure P 2.03 1.84 1.81 1.84 1.90 1.842.01 Z N 6.46 5.96 6.40 6.39 6.29 6.34 6.52 7r PTA (on 7.3 6.6 6.6 6.66.8 6.6 7.2

wt. 0 fiber) 7v Methylol 8.7 11.8 12.9 15.4 17 20.9

Compound %TMM 12.2 11.0 11.0 11.0 11.3 11.0 12.0

L01 As Cured 0.444 0.377 0.356 0.331 0.324 0.316 0.302 Aegt erhl Home0.308 0.352 0.372 0.342 0.318 0.326 0.305

as After 20 0.223 0.341 0.375 0.348 0.333 0.334 0.312

Home Washes After 20 Home Washes P 0.99 1.28 1.60 1.98 1.64 1.82 1.82 N1.51 4.69 5.81 6.11 5.99 6.45 6.25 of lnitial 49 70 88 107 86 99 91 PRetained t 1 Hand after 1 Home Wash 5 4-5 4 4 4-3 3 2 These results showthe superiority of methylolphosphoric triamide/trimethylolmelaminecompositions over phosphoric triamide/trimethylolmelamine compositionsfor imparting flame resistance. Further, they show that the flameresistance imparted by the diand higher formaldehyde adducts improveswith launderings. They also demonstrate the minimal loss of hand incellulosic fabrics treated with the compositions conded onto 8-oz.cotton twill fabric samples to net solution pickups of about 87 percent.The padded fabrics were dried at 115C. and then cured for 4 minutes at165C. The cured fabrics were laundered 20 times. Elemental chemicalanalyses of the fabric samples as cured (before laundering) and after 20launderings were made. LOl tests for flame resistance were made cured,after one laundering and after 20 launderings.

taining (monoto tri-)methylolphosphoric triamides. 50 The followingtable summarizes the results.

% Trimethylol PTA (on weight of fiber) Found P Re- Trimethylol (from P,NLOl tained Atomic Ratio N/P PTA in Bath Calcd analyses) Initial 1 HW 20HW (20 HW) Initial 20 HW These results show the efficiency oftrimethylolphosphoric triamide in imparting flame resistance to cottonWt. Additive on Fabric fabric and the durability of that effect evenafter re- Trimethy'ol PTA TMM peated laundering. 20 0.204

EXAMPLE 5 8.7 7 0.293 Dimethylolphosphoric Triamide/Trimethylolmela- 00-243 19.5 0 0.290 mine Treatment of Cotton Blend Fabrics 241 0 197Dimethylolphosphoric triamide was prepared in solution from phosphorictriamide (PTA) according to the EXAMPLE 7 procedure of Example 1 exceptthat 16.7 parts, instead of 25 parts, of aqueous formaldehyde wereemployed. Trlmethylolphosphorlc TrldlKile/Ammoplast Resm Six padbathswere prepared from the solution, each Treatment of Cotton FaPncneutralized to pH 7.2 and containing trimethylolmela- SlX aqueouspadbaths (designated A through were mine (TMM) and .05 w i h percent fammonium prepared so as to contain, per 100 parts of solution, 12chloride (curing agent). The padbaths were padded Parts oflrlmethylolphosphonc trlamlde; 1 P of onto commercial lightweight,2.8-oz. and 53-02. 50/50 y i i hydrochlqnde (curing polyester/cotton a d35- 50/50 rayon/cotton b1 d agent) and a water soluble ammoplast resinprecondenfabrics, the fabrics were dried, and curing was carried SateShown in the following table are the preconden' out in a manner similarto the procedures previously sates a the a ou which e added l g withdescribed. The following table summarizes the results the triamide andcuring agent) to the padbaths to P of the evaluations of the treatedfabrics. i e equivalen nitrogen c n nts.

Wt. 7r Dimethylol PTA Wt.% L01 Fabric (on weight of fiber) TMM Initial lHW 20 HW Hand 2.8 oz. polyester/cotton I 1.3 7.0 0.236 0.237 0.234 4 2.8oz. polyester/cotton 18.3 7.0 0.244 0.247 0.245 3-4 5.3 oz.polyester/cotton 13.1 7.7 0.251 0.249 0.244 3 5.3 oz. polyester/cotton21.6 7.7 0.257 0.259 0.259 2 3.6 oz. rayon/cotton 9.6 8.0 0.276 0.2760.284 4 3.6 oz. rayon/cotton 16.6 8.0 0.277 0.294 0.300 3-4 EXAMPLE 6 AB C D E F Trimethylolphosphoric Triamide Treatment of Cot-Trimethylolphosphoric 12 12 12 12 12 12 Fabrics c ll r i i l f ent l 1 ll l l Thisexample shows the beneficial effect that can be Trimgthyoimeiamine 8 realized through use of the combination of trimethylol- Fig g i l0 phosphoric triamide and trimethylolmelamine (TMM) 1,3455hydroxymethylyz 17 in imparting flame resistance to fabrics. Thetrimeangdglolldtiiae t D 5 31 thylolphosphoric triam de was preparedfrom phosgfi fi phoric triamide according to the procedure described3-pi g -5. 17 in Example 1. Padbaths were prepared in a manner mazme- W87 79 77 70 56 70 similar to that described in Example 5. The impregamnated fabrics (8-ounce cotton twill fabric) were dried at 115C., curedat 165-l75C. and given one home wash. The following table summarizes theresults of the evalumlons of the treated fabncsr The padbaths werepadded (at 87 percent add-on) unto mercerized bleached cotton twill 8-ozfabrics (also des- Wt, '7 Additi m Fubri. ignated A through F tocorrespond to padbaths A k L through F). The padded fabrics were driedat 100C. Trimelhylol PTA TMM L01 for 10 minutes, then cured at 165C. for4 minutes. The

0 8 0189 following table summarizes the results of the evalua- 0 160.195 tions of the treated fabrics.

A B C D E F 2 lnitial 0.251 0.295 0.263 0.244 0.261 0.233 After 1 homewash 0.245 0.296 0.270 0.250 0.254 0.239 After 20 home washes 0.2290.302 0.276 0.248 0.206 0.233

VFT (in inches) lnlthl 4.8 0.75 1.4 4.1 2. 4.0 After 20 home washes BEL1.3 0.6 4.5 BEL 3.3

Wt. P on Fabric lnitial 1.41 1.35 1.36 1.35 1.28 1.31

% of lnitial P Retained Afier 20 home washes 87 49 88 The embodiments ofthe invention in which an exclusive property or privilege is claimed aredefined as follows:

1. Methylolphosphoric triamide having the formula Milt :r

1 wherein at least one of the six R groups is CH OH and wherein 1-5 ofthe six R groups are CH OH and the remainder are H, said triamide beingcharacterized by the presence in its P-3l nuclear magnetic resonancespectrum of a band in the range 15-20 ppm. downfield from O percentaqueous phosphoric acid as external standard, which process comprisesreacting phosphoric triamide and at least one molar equivalent offormaldehyde in an aqueous medium at a pH of 7-1 1 until the reactionmixture shows said band in its nuclear magnetic resonance spectrum.

5. The process of claim 4 wherein 2-3 molar equivalents of formaldehydeare reacted with the phosphoric triamide.

6. The process of claim 4 wherein the reaction is carried out at a pH of9.5l0.5.

1. METHYLOPHOSPHORIC TRIAMIDE HAVING THE FORMULA
 2. The triamide ofclaim 1 wherein the number of CH2OH groups is 2-3 and the P-31 spectrumis free of a band at 22.5 ppm.
 3. The triamide of claim 2 wherein thenumber of CH2OH groups is three.
 4. Process for preparing amethylolphosphoric triamide having the formula
 5. The process of claim 4wherein 2-3 molar equivalents of formaldehyde are reacted with thephosphoric triamide.
 6. The process of claim 4 wherein the reaction iscarried out at a pH of 9.5-10.5.